The
United Kingdom of Great Britain and Ireland was the formal name and the state form of the
United Kingdom from 1 January 1801 until 12 April 1927. It was formed by the merger of the
Kingdom of Great Britain (itself having been a merger of the Kingdoms of
England and
Scotland) and the
Kingdom of Ireland, with Ireland being governed directly from
Westminster through its
Dublin Castle administration.
Following Irish independence on 6 December 1922, when the 1921 Anglo-Irish Treaty came into effect, the name continued in official use until it was changed to the United Kingdom of Great Britain and Northern Ireland by the Royal and Parliamentary Titles Act of 1927. The part of the island of Ireland that remained seceded from the United Kingdom in 1922 was succeeded by the state of Ireland in 1937.[1]
Under the terms of the Act of Union, the separate Parliament of Great Britain and the Parliament of Ireland were abolished and replaced by a united Parliament of the United Kingdom.[2] The new House of Commons consisted of all Members of Great Britain's 18th Parliament and 100 Irish MPs co-opted in a special election in 1801.[2] The new House of Lords consisted of all members of Great Britain's House of Lords, as well as four Lords Spiritual and twenty-eight Lords Temporal from the Irish House of Lords.[2] The new Parliament met in the Palace of Westminster, formerly the home of the Parliament of Great Britain and, until 1707, the Parliament of England.
Part of the trade-off for Irish Roman Catholics, who since 1652 were barred from voting or attending Parliament altogether under the Cromwellian Act of Settlement, was to be the granting of Catholic Emancipation, which had been fiercely resisted by the all-Anglican Irish Parliament. However, this was blocked by King George III who argued that emancipating Roman Catholics would breach his Coronation Oath to act as protector of Protestantism.
